1. Field of the Invention
The present invention relates to a magnetic recording and reproducing device, and more particularly, to an audio/control head assembly of a magnetic recording and reproducing device with an improved structure that an audio/control head is mounted at a main chassis.
2. Description of the Background Art
FIG. 1 shows the construction of a magnetic recording and reproducing device in accordance with a conventional art.
As shown in FIG. 1, the conventional magnetic recording and reproducing device includes: a main chassis 102; reel driving mechanism 110 and 112 installed in the main chassis 102 and driving a feeding reel 106 and a winding reel 108 of a tape cassette 104; a head drum 116 for reproducing a signal recorded at the tape 114 or recording a signal on the tape 114; an audio/control head 118 for deleting, recording and reproducing an audio signal, and recording and reproducing a control signal; and a plurality of posts and a guide roller for guiding a traveling of the tape 114 released from the tape cassette 104.
A tensile force of the tape 114 released from the feeding reel 106 of the tape cassette 104 is controlled by a tension post 120, and after the tape 114 passes the tension post 120, it is guided by a guide post 122 and transmitted to a erasing head 124. The erasing head 124 erases a signal recorded on the tape 114 in a recording mode.
After passing the erasing head 124, the tape 114 is guided to the head drum 116 by feeding and winding guide posts 126 and 128 and feeding and winding slant posts 130 and 132 respectively installed at both sides of the head drum 116. The head drum 116 reproduces a signal recorded on the tape 115 or records a signal on the tape 115.
After passing the winding slant post 132 and the guide post 128 via the head drum 116, the tape 115 passes the audio/control head 118. The audio/control head 118 deletes, records reproduces an audio signal, and record and reproduces a control signal.
After passing the audio/control head 118, the tape 114 passes a guide post 134, during which its travel height is controlled, and a capstan shaft 136 is installed at a position after the guide post 134, to provide a traveling force to the tape 114.
The capstan shaft 136 is an output shaft of a capstan motor (not shown) installed at the opposite side of the main chassis 102, and according to the rotation direction of the capstan motor, the traveling direction of the tape is determined.
A pinch roller 138 is provided at one side of the capstan shaft 136, being selectively attached to the capstan shaft 136, to provide a force for pulling the tape 114.
After passing the capstan shaft 136, the tape 114 is guided by a winding post 140 and wound on the winding reel 108.
The structure that the audio/control head is mounted in the main chassis of the magnetic recording and reproducing device as described above will now be explained.
Referring to an engaging structure of the audio/control head in FIGS. 2, 3 and 4, the audio/control head 118 is mounted at one side of the head base 150, the head base 150 is engaged with a mounting bracket 154 so that its height can be controlled by adjustment bolts 152a, 152b and 152c, and the mounting bracket 154 is fixed at the main chassis 102 by a fixing bolt 156.
As shown in FIGS. 2 and 5, the head base 150 is formed as a flat type roughly making a triangle shape, the audio/control head 118 is fixed at one side thereof, and through holes 158a, 158b and 158c are formed at the three corner portions, through which the adjustment bolts 152a, 152b and 152c penetrate.
The two through holes 158b and 158c are formed in a slot shape, and one through hole 158a is formed in a circular shape.
As shown in FIGS. 2, 5 and 6, the mounting bracket 154 includes an engage hole 160 through which the fixing bolt 156 passes whereby the mounting bracket 154 is mounted at the main chassis 102 by the fixing bolt 156, and three spiral holes 162a, 162b and 162c which are formed relatively high, to which the adjustment bolts 152a, 152b and 152c are engaged after passing the through holes 158a, 158b and 158c of the head base 150.
An adjustment slot 164 is formed at an end portion extended from one side of the mounting bracket 154 to adjust a distance between the head drum 116 and the audio/control head 118 by inserting an adjustment tool therein.
A first spring sheet 170 is formed at a lower surface of the head base 150, into which a spring 168 is inserted, and a second spring sheet 172 is formed at a position facing the first spring sheet 170 of the main chassis 102. A spring 168 is installed between the first spring sheet 170 and the second spring sheet 172 to elastically support the head base 150.
A hinge protrusion 174 is formed at an upper surface of the main chassis 102 and a hinge hole 176 is formed at a lower surface of the mounting bracket 144, so that the hinge protrusion 174 is inserted into the hinge hole and the mounting bracket 154 is rotated.
Referring to an assembly process of the conventional audio/control head constructed as described above, an audio/control head 118 is fixed at the head base 150 and the three adjustment bolts 152a, 152b and 152c pass the through holes 158a, 158b and 158c of the head base 150 so as to be engaged with the spiral holes 162a, 162b and 162c of the mounting bracket 154. At this time, the spring 168 is installed between the first spring sheet 170 and the second spring sheet 172.
And then, after the hinge protrusion 174 of the main chassis is inserted into the hinge hole 175 of the mounting bracket 154 where the head base 150 is installed, the fixing bolt 156 passes the fixing hole 160 of the mounting bracket and is engaged with the main chassis 102, thereby completing the assembly.
The adjustment of the audio/control head of the conventional art is made as follows.
First, the heights of the erasing head 124 and the audio/control head 118 are rendered to correspond to each other. That is, the height of the audio/control head 118 is adjusted corresponding to the height of the erasing head 124 by ascending the adjustment bolts 152a, 152b and 152c. 
At this time, the head base 150 is elastically supported by an elastic force of the spring 168 so as to maintain the height adjusted by the adjustment bolts 152a, 152b and 152c. 
Next, a tensile force is suitably maintained in a state that the audio/control head 118 is in contact with the tape 114 by ascending the adjustment bolts 152a, 152b and 152c, and then, a tilt adjustment is performed to adjust a tilt of the audio/control head 118 to heighten a sound output.
Thereafter, an azimuth adjustment is performed such that the adjustment bolts 152a, 152b and 152c are ascended to correspond a recording angle of an audio signal and an angle of the gap portion of the audio/control head 118, thereby adjusting a tilt at the side of the traveling direction of the tape 114 so as to make the maximum sound output.
Finally, an X-distance adjustment is performed to maintain a compatibility by adjusting a distance between an image signal and an audio/control signal on the tape which are simultaneously recorded by adjusting a distance difference between the head drum 116 and the audio/control head 118.
That is, after unbolting the fixing bolts 152a, 152b and 152c, an adjustment tool is inserted into the adjustment slot 164 of the mounting bracket 154 and the mounting bracket 154 is rotated centering around the hinge protrusion 174 formed at the main chassis 102, thereby adjusting the X-distance. After the adjustment is completed, the fixing bolts 152a, 152b and 152c are engaged to fix the adjusted position.
However, in the engagement structure of the audio/control head of the conventional magnetic recording and reproducing device, the audio/control head is fixed at the head base, the head base is adjustably engaged at the mounting bracket, and the mounting bracket is fixed at the main chassis to adjust the position of the audio/control head. Therefore, many parts are required for the engagement of the audio/control head and the position adjustment, resulting in an increase in a fabrication cost. Also, since the number of parts is increased, an assembly time is lengthened, and the assembly work is complicated.